i had a little accident in my 2004 545i with adaptive headlights, so i need to replace my right headlight. i bought one on ebay but my old ballast doesnt fit in my new headlight. i was just curious if you guys knew where i can find the part number on the headlight itself? i want to cross check it on realoem to see if its maybe a newer or older model headlight. or if any of you guys know why my original xenon ballast doesnt fit in my new headlight. or how can i be sure the new headlight is adaptive? thanks guys any help will be appreciated